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We presented the synthesis of isoindolone spirosuccinimides via the Rh(i)-catalysed reaction of aromatic amides that contain a (2-methylthio)aniline directing group with maleimides. Several possible reaction paths were examined by DFT calculations.

A palladium-catalyzed reaction of N-phthaloyl hydrazones derived from aldehydes and cyclobutanones, leading to the production of nitriles, is described.

The rhodium(II)-catalyzed, branch-selective C–H alkylation of aryl sulfonamides with vinylsilanes was recently developed by our group, and the unique reactivity and selectivity of the reaction was ...

Nucleophilic aromatic substitution (SNAr) reactions of non-activated aryl fluorides with amide enolates are reported. DFT calculations suggest that the reaction proceeds through a concerted SNAr pathway.

The rhodium(III)-catalyzed oxidative C–H alkenylation and coupling sequence of unprotected 1-naphthylamines with α,β-unsaturated esters, which were recently developed by our group, provide an effic...

The branch-selective C–H alkenylation with alkenes using an iridium catalyst is reported. The Ir(III)-catalyzed reaction of aniline derivatives that contain a pyrimidine-directing group with vinyls...

The palladium-catalyzed 1,1-alkynylbromination of terminal alkenes with a silyl-protected alkynyl bromide is reported. The method tolerates a diverse range of alkenes including vinylarenes, acrylates, and even electronically unbiased alkene derivatives to afford propargylic bromides regioselectively. Mechanistic studies and DFT calculations indicate that the 1,1-alkynylbromination reaction proceeds via the migration of the Pd center followed by the formation of a π-allenyl Pd intermediate, leading to the stereoselective reductive elimination of the C(sp3)–Br bond at the propargylic positon., The first Pd-catalyzed 1,1-alkynylbromination of terminal alkenes using alkynyl bromides, which provides direct access to a variety of functionalized propargylic bromides without the need for an external brominating reagent, is reported.

Dynamic asymmetric induction (DYASIN) of racemic dynamic chiral heterohelicenes afforded their highly enantioenriched forms (up to 96% ep) in quantitative yields. These heterohelicenes were readily converted into semi-static axial-chiral 1,1'-binaphthyl derivatives in a stereospecific manner.

The metal-free

To obtain enantioenriched chiral organic molecules, numerous optical resolution and asymmetric synthetic methods have been developed to date. Herein, we introduce a new approach termed dynamic asym...

The nickel-catalyzed reductive cleavage of esters in the absence of an external reductant, which involves the cleavage of an inert acyl C-O bond in O-alkyl esters is reported. Various groups, such as N-containing heterocycles, esters, amides, and even arene rings can function as a directing group.

The reaction of N-heteroaromatic compounds, such as 2-aryl-pyrrole, benzimidazole, imidazole, indole, and pyrazole derivatives, with alkynes in the presence of a catalytic amount of a nickel complex results in C–H/N–H oxidative annulation. The reaction shows a high functional group compatibility. While both Ni(0) and Ni(II) complexes show a high catalytic activity, Ni(0) is proposed as a key catalytic species in the main catalytic cycle. In the case of the Ni(II) system, the presence of a catalytic amount of a strong base, such as KOBut, is required for the reaction to proceed. In sharp contrast, a base is not required in the case of the Ni(0) system. The proposed mechanism is supported by DFT studies.

The fluoride anion-initiated reaction of phenyl aromatic carboxylates with (trifluoromethyl)trimethylsilane (Me3SiCF3) that results in the formation of O-silyl-protected 2-aryl-1,1,1,3,3,3-hexafluoroisopropanols is reported. A phenoxide anion, generated during the trifluoromethylation of the phenyl carboxylate, also activates the Me3SiCF3, which permits a catalytic amount of the fluoride anion source to be used. Various functional groups, which can be used for further elaboration, are tolerated in the reaction.

Density functional theory (DFT) was used to unveil intimate mechanistic insights on the monodentate-chelation system that is used in the Ni-catalyzed C–H/N–H oxidative annulation of aromatic amides with alkynes, a reaction that was originally reported by our group Chem Sci. 2017, 8, 6650−6655, DOI: 10.1039/C7SC01750B). The proposed reaction mechanism involves two reaction paths. The initial path is initiated by Ni(II), and the other, the main catalytic cycle, is initiated by Ni(0). Both paths require the presence of a catalytic amount of KOBut. The results of the DFT studies presented here indicate that the rate-determining step in the initial Ni(II) system involves a concerted metalation–deprotonation (CMD) mechanism and an anionic Ni(0) ate complex is the key intermediate in the main catalytic cycle. Furthermore, a previously proposed oxidative addition–alkyne insertion sequence is revised to a ligand-to-ligand hydrogen transfer (LLHT) mechanism, which is the rate-determining step in the main catalytic...

Nickel-catalyzed benzylation reactions of C−H bonds in aromatic amides with benzyltrimethylammonium halides are developed by using a 5-chloro-8-aminoquinoline derivative as a bidentate directing group. Benzylation occurs selectively at the ortho-C−H bonds in aromatic amides, and no methylation was detected. The presence of a 5-chloro-8-aminoquinoline moiety is essential for the success of this reaction, in which a variety of functional groups can be tolerated.

The reaction of ortho-methyl-substituted aromatic amides with maleimides in the presence of Pd(OAc)2 and AgOAc results in C–H alkylation at the ortho-methyl C–H bond. DFT calculations indicate that the formation of a five-membered palladacycle is a kinetically favorable step, but the insertion of the maleimide into the six-membered palladacycle is energetically favored.

The highly enantioselective synthesis of planar-chiral nine-membered cyclic amides was achieved by the Pd-catalyzed asymmetric allylic cyclization of achiral linear precursors in the presence of a catalytic amount of chiral ligand.

We report the development of a new system for C–H functionalizations catalyzed by nickel complexes. The findings show that aromatic amides with a simple directing group can participate in Ni-catalyzed C–H functionalization., The Ni-catalyzed reaction of aromatic amides with alkynes in the presence of KOBut involves C–H/N–H oxidative annulation to give 1(2H)-isoquinolinones. A key to the success of the reaction is the use of a catalytic amount of strong base, such as KOBut. The reaction shows a high functional group compatibility. The reaction with unsymmetrical alkynes, such as 1-arylalkynes, gives the corresponding 1(2H)-isoquinolinones with a high level of regioselectivity. This discovery would lead to the development of Ni-catalyzed chelation-assisted C–H functionalization reactions without the need for a specific chelation system.

The ruthenium-catalyzed direct alkynylation of arenes with the chelation assistance of nitrogen-containing heterocycles including pyridine, pyrimidine, pyrazole, and imidazole are described. The alkynylation is successful even in the presence of an acidic N–H bond. Broad compatibility with functional groups is observed under catalytic conditions. The obtained alkynylated products could serve as precursors for polycyclic heteroarenes.

The palladium-catalyzed direct alkynylation of C-H bonds in aromatic carboxylic acid derivatives is described. The use of 8-aminoquinoline as a directing group facilitates the alkynylation of an electronically diverse range of C(sp(2))-H bonds.

The rhodium(I)-catalyzed regioselective silylation of the ortho carbon-hydrogen bond in 2-arylpyridines with disilane is described. For example, the reaction of 2-(2-methylphenyl)pyridine with 2 equivalents of hexamethyldisilane in the presence of 5 mol % [RhCl(cod)](2) (cod=1,5-cyclooctadiene) in o-xylene at 130 degrees C for 15 h gave 2-[2-methyl-6-(trimethylsilyl)phenyl]pyridine in 86 % yield. In contrast to silylation with hydrosilanes, hydrogen acceptors are not required to achieve high conversion. A variety of substituents, including alkoxy, amine, ester, and fluorinated groups, are compatible with this catalysis. When substrates containing two ortho C-H bonds are used, monosilylated products are obtained selectively by utilizing the 3-methyl-2-pyridyl group as a directing group.

The highly enantioselective synthesis of planar-chiral nine-membered cyclic amides was achieved by the Pd-catalyzed asymmetric allylic cyclization of achiral linear precursors in the presence of a catalytic amount of chiral ligand.

The first catalytic alkynylation of unactivated C(sp(3))-H bonds has been accomplished. The method allows for the straightforward introduction of an ethynyl group into aliphatic acid derivatives under palladium catalysis. This new reaction can be applied to the rapid elaboration of complex aliphatic acids, for example, via azide/alkyne cycloaddition.

Palladium-catalyzed ortho-alkynylation of aromatic C-H bonds in anilides is described. Preliminary mechanistic studies reveal that electrophilic palladation is involved. Synthetic elaborations of alkynylated products are also demonstrated.

The process allows the synthesis of various o-substituted bisarenes, which can serve as precursors of polycyclic systems as is demonstrated for the preparation of heteroarene (X).

The aminoquinoline directing group promotes the ortho-alkynylation without the need of any silver salts.

The new catalytic system takes advantage of the chelation assistance by the 2-pyrididylmethylamine moiety.

Although the pioneering example of ortho metalation involving cleavage of C–H bonds was achieved using a nickel complex (Kleiman, J. P.; Dubeck, M. J. Am. Chem. Soc. 1963, 85, 1544), no examples of catalysis using nickel complexes have been reported. In this work, the Ni-catalyzed transformation of ortho C–H bonds utilizing chelation assistance, such as oxidative cycloaddition of aromatic amides with alkynes, has been achieved.

Palladium-catalyzed ortho-alkynylation of aromatic C-H bonds in anilides is described. Preliminary mechanistic studies reveal that electrophilic palladation is involved. Synthetic elaborations of alkynylated products are also demonstrated.

A rhodium-catalyzed silylation reaction of carbon−cyano bonds using disilane has been developed. Under these catalytic conditions, carbon−cyano bonds in aryl, alkenyl, allyl, and benzyl cyanides bearing a variety of functional groups can be silylated. The observation of an enamine side product in the silylation of benzyl cyanides and related stoichiometric studies indicate that the carbon−cyano bond cleavage proceeds through the deinsertion of silyl isocyanide from η2-iminoacyl complex B. Knowledge gained from these studies has led to the development of a new intramolecular biaryl coupling reaction in which aryl cyanides and aryl chlorides are cross-coupled.

The rhodium(I)-catalyzed regioselective silylation of the ortho carbon-hydrogen bond in 2-arylpyridines with disilane is described. For example, the reaction of 2-(2-methylphenyl)pyridine with 2 equivalents of hexamethyldisilane in the presence of 5 mol % [RhCl(cod)](2) (cod=1,5-cyclooctadiene) in o-xylene at 130 degrees C for 15 h gave 2-[2-methyl-6-(trimethylsilyl)phenyl]pyridine in 86 % yield. In contrast to silylation with hydrosilanes, hydrogen acceptors are not required to achieve high conversion. A variety of substituents, including alkoxy, amine, ester, and fluorinated groups, are compatible with this catalysis. When substrates containing two ortho C-H bonds are used, monosilylated products are obtained selectively by utilizing the 3-methyl-2-pyridyl group as a directing group.

A rhodium-catalyzed silylation reaction of carbon-cyano bonds using disilane has been developed. Under these catalytic conditions, carbon-cyano bonds in aryl, alkenyl, allyl, and benzyl cyanides bearing a variety of functional groups can be silylated. The observation of an enamine side product in the silylation of benzyl cyanides and related stoichiometric studies indicate that the carbon-cyano bond cleavage proceeds through the deinsertion of silyl isocyanide from eta(2)-iminoacyl complex B. Knowledge gained from these studies has led to the development of a new intramolecular biaryl coupling reaction in which aryl cyanides and aryl chlorides are cross-coupled.